Known wind turbines used for wind turbine generator include those having wind turbine rotor blades with a fixed pitch angle and those having wind turbine rotor blades with a variable pitch angle.
An example of a known mechanism for changing the pitch angle of the above wind turbine rotor blades is a mechanism by which linear movement of a rod in a hydraulic cylinder is converted into rotation of a wind turbine rotor blade about the axis thereof (see, for example, Patent Document 1).
Besides the mechanism described in Patent Document 1 above, a variable-pitch configuration is known in which a hydraulic cylinder is supported on a rotor head so as to be rotatable about a single axis by a trunnion structure while an end of a rod is supported on a wind turbine rotor blade so as to be rotatable about a single axis.
This variable-pitch configuration holds the hydraulic cylinder and the rod so as to be rotatable about the trunnion structure in a plane perpendicular to the axis of the wind turbine rotor blade. Because the end of the rod is supported at a distance from the axis of the wind turbine rotor blade, linear movement of the rod is converted into rotation of the wind turbine rotor blade about the axis thereof.
Patent Document 1:
Japanese Unexamined Patent Application, Publication No. HEI-5-149237